Process and an apparatus for controlling the weft threads in weaving looms



3 Sheets-Sheet 1 w w a r w June 1, 1965 H. scHAFFER PROCESS AND AN APPARATUS FOR CONTROLLING I THE WEFT THREADS IN WEAVING LOOMS Filed Feb. 15, 1962 June 1, 1965 H. scHAFFER 3,186,444

PROCESS AND AN APPARATUS FOR CONTROLLING THE WEFT THREADS IN WEAVING LOOMS 3 Sheets-Sheet 2 Filed Feb. 13, 1962 ATTORNEY8 June 1, 1965 H. scHAFFER 3,185,444

PROCESS AND AN APPARATUS FUR CONTROLLING THE WEFT THREADS IN WEAVING LOOMS 3 Sheets-Sheet 3 Filed Feb. 13, 1962 INV ENT OR Heinnkh JcIzaf/kr wa wim fww ATTORNEYS United States Patent ice 9 Claims. cl. 1ss-s70 The invention relates to a process and an apparatus for controlling the weft threads in weaving looms.

Mechanical methods have hitherto been used for controlling the weft threads in weaving looms. For this purpose, a weaving loom is provided with a weft fork approximately in the middle of the fabric. This fork acts as a feeler for the weft thread and arrests the loom when it detects no weft thread. In the usual loom with a shuttle containing a weft spool, the mechanical weft thread control involves the risk that the weft threads may be pushed out of the fabric by the weft fork, thereby producing faults in the web in the form of so-called weft eyes. Moreover, these known mechanical devices do not detect breaks in the weft thread near the edges of the fabric. In a weaving loom operating with gripper shut tles, which have no spool, these disadvantages are even more serious because the weft thread is usually inserted in the shed without tension. In weaving looms operating with gripper shuttles, the use of the known mechanical weft thread controls is therefore practically impossible.

The invention relates to a process and an apparatus for pneumatic weft thread control. In accordance with the invention, air suction is exerted in the region of the edges of the web or close thereto, this suction taking in the weft threads if present, with suction elements provided with suction apertures for taking in the weft threads and communicating with a suction pipe being provided for this purpose on the sley of the loom in the region of the edge of the web or close thereto.

In a weaving loom in which weft thread for two throws or only one throw is taken from the spools arranged on both sides, and the weft threads are taken up by a gripper shuttle and inserted in the shed alternately from the right and the left so that weft threads originating from the right and left side of the loom respectively alternate in the finished fabric, it is known to provide a suction aperture in the sley path close to the edges of the web, the ends of the weft threads being sucked into these apertures by means of a .suction device. This arrangement, however, is intended merely for smoothing out the weft threads and is not a device for controlling the weft threads.

By my US. application SN. 50,430, new Patent No. 3,050,088, a weaving loom is also known in which weft thread for two throws is taken from spools arranged on both sides, and the weft threads are inserted alternately from the right and left into the shed by means of a gripper shuttle, the threads on release from the shuttle being subjected to a tension exerted by the suction pro duced by suction tubes arranged along both edges of the web. As the shuttle approaches, these tubes enter the shed and the weft threads are sucked into these tubes 3,185,444 Patented June 1, 1965.

as they slide off the shuttle and thereby moved out of the shed together with the shuttle. This arrangement is intended merely to smooth out the weft thread.

The basic idea of the process of the invention for controlling the weft thread consists in that the known apparatus for applying suction to the weft threads near the edges of the web is used not only for smoothing out the weft thread but for controlling the thread. This is achieved by the fact that the increase in suction which occurs when the weft thread is sucked into the apparatus is utilised for making an electric contact which keeps the weaving loom in action, whereas when this contact is not made, the weaving loom is put out of action.

The apparatus for carrying out this process comprises, in addition to the known suction elements and pipes, a movable element and pipe subjected to the action of a spring, the vacuum in each suction pipe acting on the corresponding movable element; the apparatus further comprises an electric contact which, when the vacuum in a particular suction pipe is increased beyond a certain value, is either opened or closed by the movable element.

The process and apparatus according to the invention provide a sensitive and reliable means of weft control which cannot impair the fabric in any way. It controls any ruptures in the weft thread occurring in any part of the fabric. In addition, the weft threads are smoothed out by the apparatus. Moreover, it is possible to combine the new process and apparatus for controlling weft threads with the known apparatus for smoothing out weft threads in weaving looms operating with gripper shuttles.

In a weaving loom operating with a shuttle containing a shuttle spool, the suction elements according to the invention consist of hollow suction plates fixed to the sley next to the edges of the web. The upper surface of these suction plates are provided with suction slots extending in the direction of the weft threads. For looms operating with gripper shuttles, in which suction tubes are arranged along both edges of the fabric, which tubes enter the shed when the shuttle approaches, suck in the weft thread as is slides from the shuttle, and then leave the shed together with the shuttle, the suction tubes. are so arranged that they may be utilised as suction elements lies substantially parallel to the shuttle, and the wall of the tapered. part nearest the shuttle has a number of adjacent suction apertures. This combination of suction element for thread control with suction tubes for smoothing out the weft threads may be used for thick weft threads. apertures of the tubes are connected to a separate suction pipe. which is independent of the main suction pipe. To obtain the necessary suction and utilise the pressures in the suction pipes for control purposes, one embodiment of the invention is provided with a suction pump foreach suction element. The cylinder of the pump is swingably attached to the sley, and its piston and piston rod are hingeably connected with an arm of a toggle lever which is swingably attached to the framework of the loom. The other arm of the, toggle lever is provided with a contact which is situated opposite a slidable contact pin which is under the action of a spring and attached to. the frame- For thin weft threads, one or more suction.

r 2: work of the loom. Up to a certain suction value, a spring acting on the toggle lever prevents the piston and piston rod, and hence the toggle lever, being moved by the suction cylinder connected to the sley, and stops are provided which limit the movement of the toggle lever to a certain range.

In order that the contact pin may automatically be adjusted to the optimum distance from the arm of the toggle lever which has the contact, the contact pin is preferably so constructed and arranged that it may easily be displaced by the toggle lever but will return to its starting position with some retardation under the action of its spring.

In another embodiment of the apparatus according to the invention, the pressures in the suction pipes are utilised for control purposes by providing in each suction pipe leading to a suction element a housing with a metal membrane dividing it airtightly into two parts. The

part of the suction pipe connected with the suction element opens into one half of the housing and a tube with an air inlet of adjustable cross section is connected to the other half of the housing. The part of the suction pipe leading from the suction device to the housing forks into two arms of equal cross-section before reaching the housing. One arm is connected to one half of the housing andthe other is connected to the other half. The membrane is connected to an electric circuit. The half of the housing into which the part of the suction pipe connected with the suction element opens contains an adjustable contact which makes contact with the membrane when the pressure in that part of the housing falls to a certain level.

In another embodiment of the apparatus, the contact arranged in one half of the housing as described above may be replaced by an adjustable contact arranged in that other half of the housing. The membrane may touch this contact when at rest and may move away from it when the pressure in the other half of the housing falls below a certain value.

Various circuits and elements for starting or stopping the loom when the contacts are closed or opened may be used. Various means for producing air suctionmay be used, except for the construction of the thread control device, in which a suction pump serves also as control. For example, it is possible to use suction devices which control the weft threads of several looms.

Various examples of thread control devices according to the invention are illustrated diagrammatically in the accompanying drawing, in which:

FIGURE 1 is a longitudinal section through a suction plate for weaving looms using shuttles containing'shuttle spools;

FIGURE 2 is a side elevation of a suction tube for weaving looms using gripper shuttles;

FIGURE 3 is a side elevation of another suction tube for weaving looms using gripper shuttles;

FIGURE 4 is a side elevation, partly in longitudinal section, of an embodiment of the apparatus comprising a suction pump, a toggle lever and a displaceable contact P FIGURE 5 is a longitudinal section through another form of movable contact pin for the embodiment of FIGURE 4;

FIGURE 6 is a longitudinal section of an apparatus with a housing having membrane arranged in the suction pipe;

. FIGURE 7 is a perspective view of a portion of a loom, showing the sley, reed and shuttle, with the suction control of the form shown in FIGURE 4 coupled to the sley, and, diagrammatically, a control circuit and part of a conventional loom stopping mechanism; and,

FIGURE 8 is a perspective view similar to FIGURE 7 but showing the control means illustrated in FIGURE 6.

The suction plate illustrated in FIGURE 1 and provided for normal weaving looms has an inner cavity 11.

On the upper surface of this plate 10 are a number of suction slots 12 arranged in a row and communicating with cavity 11. On its undersurafce, the suction plate 10 has an opening 13 which communicates with the cavity 11 and is connected to suction pipe 14. Plates It) as shown in FIGURE 1 are mounted on the sley of the loom near the edges of the fabric in such a manner that the shuttle can move through freely and the position of the slots 12 corresponds to the position of the Weft threads. As soon as'the shuttle leaving he shed has passed one suction plate 1tl, the thread, if'present, is sucked in at the slots 12. This increases the vacuum in the pipe 14 connected to the plate 19. This also prevents jumping back of the weft thread into the shed, which might otherwise easily occur when the shuttle encounters the picker. When, however, the shuttle has not carried a weft thread with it, the pressure in the pipe 14 remains unchanged when the shuttle passes.

A suction tube 15 as shown in FIGURE 2 is used in Weaving looms with gripper shuttles both for smoothing out the weft threads and for controlling them. The tube 15 is tapered in the direction of its suction end. Tapered portion 16 is provided with a number of successive suction slots 17. Tubes 15 are arranged to be longitudinally displaceable on the sley along both edges of the web, with their tapered portions 16 substantially parallel to the shuttle and the slots 17 facing the shuttle. When suitably actuated, the tubes 15 enter the shed as the shuttle apporaches. The weft threads, if present, are sucked as they slide off the shuttle, and the tubes, holding the Weft threads, leave the. shed together with the shuttle. When the tubes 15 suck in and retain the weft threads, there is an increase in vacuum in these tubes and in the suction pipes connected thereto. This change in pressure does not occur when there is no weft thread.

The tube 18 shown in FIGURE 3 is similar to the tube 15 shown in FIGURE 2. The tapered portion 19 is provided with circular apertures 20 instead of the suction slots 17. In addition, the tube 18 has a separate suction slot 21 acting as weft thread control. This slot 21 is connected to a pipe 22 which is independent of the pipe of the suction tube 18 and which is introduced into the tapered portion 19 of the tube 18. Although the tube 18 is used both for smoothing out weft thread and as control, the suction elements for the two purposes are separate. When the weft thread is present, it is sucked in both through the apertures 20 and through the slot 21. This increases the vacuum in the pipe 22 connected to the slot 21. This increase in vacuum does not occur when there is no weft thread.

In the embodiment shown in FIGURE 4, cylinder 24 of a suction pump is connected to the sley 23. At its end near the sley, the cylinder 24 has a connecting pipe 25. A suction plate It or a suction tube 15 or 18 may be connected to this connecting pipe 25 through a flexible tube or the like. If a suction tube 18 is attached, pipe 25 is connected to the suction pipe 22. A piston 26 and piston rod 27 are arranged in the cylinder 24 of the suction pump. The outer end of piston rod 27 is hingeably connected with an arm 28a of a toggle lever 28 which is mounted on the pivot pin 29 fixed to the framework of the loom. The excursions of the toggle lever 28 are limited by stops 30 and 31 arranged on either side of the arm 28a on the framework of the loom. A tension spring 32 of adjustable tension acts on the other arm 23b of the lever 23. This spring tends to keep the arm 28a in engagement with the stop 30. The arm 28b is provided with a contact 33.

A longitudinally displaceable contact pin 34 is arranged on the framework of the loom below the contact 33. The contact pin 34 is carried by a displaceable fork 35 and is under the action of a helical spring 36 arranged inside the fork 35. This spring keeps the pin in its uppermost position or returns it to this position when it has been depressed by the contact 33.

FIGURE 5 shows another form of contact pin with means for mounting it to provide a dash pot. This contact pin 37 is in the form of a piston at its lower end. Piston portion 38 of this pin 37 is mounted in a cylinder 39 which is filled with a braking fluid, for example thin oil, and which is fixed adjustably to the framework of the loom by means of a support 40. A helical spring 41, which tends to keep the contact pin 37 in its upper position and returns it, to that position when it has been depressed by the contact 33, is arranged in the cylinder 39 below the piston part 38 of the contact pin 37. The piston part 38 contains a cavity 42. At the top of this cavity are outlet ducts 43 for the braking fluid. Another outlet duct 44 and a narrow duct 45 are arranged in the piston part 38 below the cavity 42. The wide outlet duct 44 together with a ball 46 arranged in the cavity 42 form a valve for permitting rapid depression of the contact pin 37 into the cylinder 39 by the contact 33. The narrow duct 45 serves to retard the outward movement of the contact pin 37 out of the cylinder 39 under the action of the helical spring 41. This retarded outward movement automatically adjusts the contact pin 37 to the optimum distance to the contact 33.

FIGURE 7 shows a portion of a loom with the control structure of FIGURE 4 connected to the sley 23. Sley 23 carries reed R, and a shuttle S carrying weft thread Tx is shown in place on the sley. Warp threads T form the shed through which the shuttle passes. A rail 72 is mounted on the front of the sley and a suction tube carrier 71 is slidable along the rail. No means for moving the carrier toward and from the shed has been shown, but mechanism for doing this is disclosed in abovementioned Patent No. 3,050,088. Carrier 71 supports a suction tube, such as the tube 15, and moves it in and out of the shed. The control suction cylinder 24 is connected to the sley as previously described.

FIGURES 4 and 7 show the apparatus with the sley 23 in its rear position. When the sley 23 moves forward (to the left), it carries the suction cylinder 24 with it. The piston 26 and piston rod 27 are not moved forward at first because they are connected to the toggle lever 28 which is under the influence of the retaining Spring 32. A vacuum is thereby produced inside the suction pump and in the suction tube connected to the suction pump. The retaining spring 32 is so adjusted that the toggle lever 28, the piston rod 27 and piston 26, remain in their position of rest when the slots 17 of the suction tube 15 are exposed. If the slots 17 are closed by a weft thread, the resulting increase in vacuum in the suction pipe and pump causes the piston 26 and piston rod and toggle lever 28 to be carried forward by the cylinder 2-4 or sley 23 against the action of the spring 32. T he contact 33 arranged on the arm 28!; of the toggle lever 28 then comes into engagement with the movable contact pin 34 to make contact, and thus operate appropriate switching elements to keep the loom in operation. If on the other hand there is no weft thread and therefore no movement of the toggle lever 28 and no contact between the contact 33 and the contact pin 34, the loom is switched off by a switch relay or the like. Although any conventional control circuit and loom cut-off means may be employed, a simple circuit and cut-off operator have been shown in FIGURE 7. The circuit includes a wire 88 from a suitable power source to the lever 28, and a wire 81 from the source to a coil 82. The opposite side of the coil is connected by wire 83 with the movable contact 34. Thus, whenever lever 28 is rocked and contacts 33 and 34 closed, the coil will be energized.

Coil 82 controls a latch lever 90 which is pivotally connected at one end to one arm 91a of a bell-crank 91, pivotally mounted at 92 for rocking movement. The free end of latch lever 96 is hooked, as at 96a, to engage the end 840 of an arm 84b of a cam follower 8- The cam follower is pivotally mounted at its center 85, and

the opposite end 84a carries a cam-following roller 86. Roller 86 is held in engagement with a cam 88 by means of a spring 87 which is connected to arm 84a of the cam follower and to a convenient part of the loom frame. Cam 88 is mounted on a shaft 89 for rotation once each movement of the sley. Arm 91b of bell-crank 91 is connected to a loom cut-off rod 93.

When a weft thread is drawn into, and closes, or partially closes, the openings 17 in suction tube 15, cylinder 24 and piston 26 and its rod 27 will move as a unit with the sley and rock lever 28 to close contacts 33 and 34. This will close the circuit to coil 82 and draw latch lever 90 upwardly out of engagement with cam-follower 84. Therefore, when cam 88 rocks cam-follower 84 no movement is imparted to bell-crank 91 and cut-off rod 93. The loom will continue in operation. If there is no weft thread to lie in the slots 17 of suction pipe 15, the free entry of air to the pipe, and through hose 70 to cylinder 24, will not be cut off and cylinder 24 may move freely with the sley without causing movement of piston 26, rod 27 and lever 28. Consequently, the circuit to coil 82 is not closed and latch lever 99 will remain in hooking engagement with cam follower 84. Under these conditions, rocking of cam follower 84 by cam 88 will cause bellcrank 91 to be rocked to pull rod 93 and stop the loom.

When the sley 23, after reaching its forward position, moves back together with the cylinder 24, the piston 26, rod 27 and lever 28 are returned to their position of rest. The air sucked into the pump is then expelled. To enable air to flow out of the suction pump, a non-return valve 47 is arranged at the end of the cylinder 24 near the sley. A portion of the air sucked into the suction pump is pressed through the connecting pipe 25 and suction pipe into the suction tube 15 and escapes through the slots 17. This has the advantage that the slots 17 cannot be obstructed by dust from the threads or the like.

When the apparatus shown in FIGURE 4 is used in conjunction with a suction tube 15 illustrated in FIGURE 2, which serves both for smoothing out the Weft thread and for controlling the thread, the suction pump must be sufficiently powerful to smooth out the thread.

In the embodiment shown in FIGURES 6 and 8 a housing 48 with membrane is arranged in the suction pipe. The necessary suction is now produced by an apparatus, not shown, which is connected to the loom, or independent of it.

FIGURE 8 shows the housing 48 arranged in operative position adjacent the sley of a loom. The sley, reed, shuttle, shed and weft thread are similar to those shown in FIGURE 7 and, therefore, are given the same reference characters primed. The electric circuit and loom control mechanism are also the same as in FIGURE 7 and these parts also have the same reference characters as in FIGURE 7, but primed.

The housing 48 is formed by two plates 49 and 5t which are connected together and have a generally lenticula-r central cavity 51. The plates 49 and 59 are made of electrically insulating material. A metal membrane 52 is stretched between these two plates so that it extends through the centre of the housing 4-8 and its cavity 51. The top end of the membrane 52 has a terminal 5 3 for an electric conductor and projects beyond the edge of the housing, as shown.

The part 54 of the suction pipe connected with a suction plate 18, a suction tube 15 or a suction tube 18 leads into the half of the housing 48 formed by the plate 50. The part 54 of the suction pipe communicates with the half of the cavity 51 situated on one side of the membrane 52 by a duct 55 in the plate 50. A tube 56 is connected to the other half of the housing 48, which is formed by the plate 49. This tube is connected in such a manner that it communicates with the other half of the cavity 51 on the other side of the membrane 52 through a duct 57 in the plate 49. The tube 56 is closed at its outer end and air inlets 53 are arranged at intervals along it. It has a rubber or plastic sleeve 59 which can be moved to cover or expose the inlets 58. The part 60 of the suction pipe leading from the suction device to the housing 43 is divided in front of the housing 48 into two arms 61 and 62. One of these arms opens into the plate 49 and the other into the plate d. The arm 61 commuicates with that half of the cavity 51 to which the tube 56 is connected, by means of ducts 63 and 64 in the plates 49 and 5t), and the arm 62 is connected to that half of the cavity 51 which commuicates with the part 54.

A contact screw 65 is arranged at the centre of the plate 50 and a terminal 66 for a conductor is connected to the screw. The tip of the screw 65 projects into the cavity 51 so that it is at some distance from the centre of the membrane 52. The distance between the membrane 52 and the tip of the screw may be regulated by adjusting the .screw. The plate 49 is provided with a contact screw 67 and a terminal 68. Depending on the desired circuit arrangement, either the contact screw 65 or the contact screw 67 is used.

When using the apparatus shown in FIGURES 6 and 8 the suction pipe 6t? sucks in air through the suction pipe 54 connected to the plate 10, suction tube 15 or suction tube 18 and through the regulating tube 56, by way of the housing 48. By exposing or covering a suitable number of inlets 58 of the regulating tube 56 by means of the sleeve 59, this suction is previously so adjusted that the same quantity of air is sucked through the part 54 and the regulating tube 56 when the slots 12 of the suction plate 10, the slot 17 of the suction tube 15 or the slot 21 of the suction tube 18 are open. The same vacuum will therefore be produced on both sides of the membrane 52 in the cavity 51, and the membrane 52 will therefore be kept in its central position. When the vacuum is raised in the part 54 by a weft thread sucked in by the suction plate or the suction tube or 18, this increases the vacuum in that half of the cavity 51 which communicates with the part 54 of the suction pipe. The central portion of the membrane 52 is thereby moved out of position towards the plate 50 and comes into contact with the contact screw 65 if the latter is suitably adjusted. A contact is released by the contact between the membrane 52 and the screw 65 so that the loom is kept in operation by the various elements of the circuit. When there is no weft thread, there is no movement of the membrane 52 towards the plate 5!) so that there is no contact between the membrane 52 and the screw 65. This results in arrest of the weaving loom through a switch relay or the like.

If the contact screw 67 is used instead of the contact screw 65, the tip of the contact screw 65 is moved out of the cavity 51 and the tip of the contact screw 67 is moved into the cavity 51 so that it is in contact with the membrane 52 when the latter is in its central position. When the membrane 52 moves towards the plate 50 as a result of a weft thread being sucked in through the suction plate 10, the suction tube 15 or the suction tube 13, the connection between the membrane and the screw 67 is opened, and the loom is thereby kept in operation. When on the other hand no weft thread is sucked in through the plate 10 or tube 15 or 18, no movement of the membrane 52 takes place and there is no interruption of the connection between the membrane and the contact screw 67, with the result that the loom is arrested.

We claim:

1. Process for controlling weft threads in a weaving loom having a stop motion normally operable each throw of the shuttle to stop the loom comprising, arranging suction intakes having open inlets in the region of the edges in the path of weft threads laid by the shuttle to grip the weft threads, utilizing weft threads being laid to restrict the inlets to increase the vacuum in the suction inlets, and employing the vacuum increase in the suction inlets as a motivating force to render the stop motion inoperative.

arsena s 2. In a weaving loom having a sley, suction elements arranged on the sley adjacent the edges of the web, each said suction element being provided with suction apertures for grasping the weft threads and communicating with a suction pipe, means to apply suction to each suction pipe, a spring controlled movable element for each suction element and each suction pipe, on which movable element the vacuum prevailing in the corresponding suction pipe acts, and switch contacts for each suction element and suction pipe, operated by the associated movable element when the vacuum in the suction pipe is increased above a certain level.

3. In a weaving loom according to claim -2,.wherein the suction elements are hollow suction plates fixed to the sley close to the edges of the web and each provided on its upper surface with suction slots extending in the direction of the weft threads.

4. In a weaving loom according to claim 2, wherein the suction elements are movable suction tubes arranged on both sides of the edges of the web, which tubes are movable to enter the shed when the shuttle approaches, suck in the weft thread when the latter slides from the shuttle, and leave the shed together with the shuttle hold-y ing the weft thread, the suction tubes being tapered towards their suction end, with their tapered portion substantially parallel to the shuttle, and the suction apertures are provided on the wall of the tapered portion facing the shuttle.

5. In a weaving loom according to claim 4, wherein at least one of the suction apertures of the suction tubes is connected to a suction pipe separate from the main suction pipe to function as the weft thread control.

6. In a weaving loom according to claim 2, wherein said movable element comprises a suction pump communicating with each suction element, said pump having a cylinder, a piston and a piston rod, said cylinder being pivoted to said sley; a toggle lever rockably mounted on said loom, one arm of said toggle lever being hingedly connected to said piston rod; said switch contacts comprising a contact on the other arm of said toggle lever and a displaceable, spring-controlled contact pin mounted on said loom and disposed opposite said first mentioned contact; a spring connected to said toggle lever and to said loom to prevent movement of said piston, piston rod and toggle lever by suction below a pre-determined value in said cylinder upon motion of said sley and cylinder; and stops for limiting motion of said toggle lever to a given range.

"7. In a weaving loom according to claim 6, wherein the free end of said contact pin is a piston movable in a cylinder to provide a dash pot, said dash pot cylinder being filled with a braking fluid and said dash pot piston including a valve for permitting rapid inward movement of said dash pot piston into said dash pot cylinder under the action of said toggle lever, a spring urging said dash pot piston out of said dash pot cylinder. and said dash pot piston also including a duct for retarding its movement out of said dash pot cylinder.

8. In a weaving loom according to claim 2. comprising a housing arranged in each suction pipe leading to said suction elements, said housing including a metal membrane as the said spring controlled movable element, said membrane dividing said housing hermetically into halves, the part of said pipe leading from said housing to said suction element opening into one said half of said housing, a tube connected to said other half of said housing, said tube having air inlet means of adjustable area, said pipe having a second part leading to said housing remote from said first-named part, said second part having two forks, said forks being connected to said halves of said housing, an electric circuit, said membrane being connected in said electric circuit, an adjustable electric contact in one of said halves of said housing, said membrane and said contact engaging and disengaging 9 10 through movement of said membrane under pressure 2,202,323 5/40 Sullivan 139'370 changes in one of said halves of said housing. 2,762,399 9/56 Moseley et al 139170.-3 9. In a weaving loom according to claim 8, wherein 2,842,164 7/58 Head 139-4703 said tube is closed at its outer end, said air inlet means include spaced air inlets and a sleeve, and said sleeve is 5 FOREIGN PATENTS movable to expose and cover said air inlets. 1 2 1 4 3 4 1 France References Cited by the Examiner 529896 11/40 Great Bmam' UNITED STATES PATENTS DONALD W. PARKER, Primary Examiner.

1,921,296 8/ 33 P001 139-127 10 MERVIN STEIN, RUSSELL C. MADER, Examiners. 1,963,098 6/34 Pool 139127 

1. PROCESS FOR CONTROLLING WEFT THREADS IN A WEAVING LOOM HAVING A STOP MOTION NORMALLY OPERABLE EACH THROW OF THE SHUTTLE TO STOP THE LOOM COMPRISING, ARRANGING SUCTION INTAKES HAVING OPEN INLETS IN THE REGION OF THE EDGES IN THE PATH OF WEFT THREADS LAID BY THE SHUTTLE TO GRIP THE WEFT THREADS, UTILIZING WEFT THREADS BEING LAID TO RESTRICT THE INLETS TO INCREASE THE VACUUM IN THE SUCTION INLETS, AND EMPLOYING THE VACUUM INCREASE IN THE SUCTION INLETS AS A MOTIVATING FORCE TO RENDER THE STOP MOTION INOPERATIVE. 